MechChem Africa September-October 2021

⎪ Maintenance and asset management ⎪

Real-time monitoring reduces impact of COVID-19 Juan Labuschagne of Martec, the Pragma Group’s condition monitoring company, describes how IIoT (Industrial Internet of Things) technology and the use of smart sensors has helped to optimise on-site maintenance delivery and limit the adverse effects of the COVID-19 Pandemic on plant operations.

S ince the arrival of COVID-19wehave experienced immensely negative im- pacts onour economy and infrastruc- ture. Various industries and sectors haveundergonemassiveoperational changes, with the focus on reducing expenditure at the forefront of most management strate- gies. Companies have been forced to reduce staff either due to financial constraints or the operational risks of spreading the disease. Compliance with compulsory restrictions or scaling down staff result in various compli- cations as regards the reliability of costly in- frastructure: reduced maintenance budgets; reduced maintenance staff and tasks; delays in critical maintenance activities; and limited contractor availability, for example. All these factors significantly increase the riskof failure of plant-critical equipment. Tokeepunexpected failures toaminimum, planned and scheduled maintenance were traditionally the ultimate strategies. The industry has since moved on, however, and a new ‘predictive maintenance’ strategy is be- ing born, thanks to smart sensors and devices with remote in-time/real-time monitoring capabilities. In this day and age, most software and machinery suppliers provide an open type of architecture toenable theflowof communica - tion and to enable integration with different processes. This new revolution (Industry 4.0) aims at industrial digitalisation and the networking of devices. This allows mass data to be stored so long-term and accurate ob- servations canbe accumulatedusing complex analytical methods. The ability to use this technology to make

informed and accurate decisions during the restrictions of the COVID-19 pandemic re- sulted invarious advantages, suchas, reduced staff requirements tocarryout physical condi- tionmonitoring tasks; effectivemaintenance planningwith contractors and staff; increased production time; increased reliability of plant equipment; and effective resource andmate- rial requirements. As an example, a large mining company was experiencing problems with unexpected failures on its electrical reticulation equip- ment, especially on medium and high voltage cables and terminations. Unexpected failures, even with only a few hours of downtime, at concentrator plants can result in the loss of millions in revenue. The decisionwasmade to place smart sensors anddevices on the cables to monitor partial discharge (PD) activity in real-time. Partial discharge is an electrical phenom- enon that causes deterioration of the elec- trical characteristics of insulation material within MV and HV equipment. PD activity can be detected using ultra high frequency (UHF) sensors and monitoring devices that collect data and process it so that engineer- ing analysis becomes possible and defects identified. Themost significant trends for PD analysis are the intensity of the pulse called theQmax (mV) and the repetition rate of this pulse per power cycle, called the pulse rate (PPS). When the PPS starts to trend upward, the first alarm is raised and the customer notified. Depending on the type of insulation system and the PD characteristic involved, a decision can be made to inspect the specific equipment for defects or to conduct further

advanced online or offline testing to identify the problem. PD problems can cause massive damage to surrounding equipment such as breakers, panels, transformers and motors, which get damaged due to cable termination failures. This results in considerable amounts of downtime. By applying modern real-time/ in-time monitoring and analysis techniques, repairing a problematic termination can take as little as four hours, and this need only af- fect one specific power feeder to the plant equipment. Substantial revenue savings can result, particularly when taking into account the advantages of a properly planned outage that best suits plant availability. Regarding the capabilityof using real-time monitoring, data analysis and trending on an IOT platform, the possibilities are endless. Customers can fully customise the views and alarm limits of any data they want to trend from any type of smart sensor, database or SCADA platformon the plant. Martec’s team of capable individuals and engineers can then analyse any triggered alarms and write informative flash reports to initiate correc - tive actions. The IIOTwill definitely be part of our ‘new normal’ going forward. The significance of having all the data in real time, with customis- able alarmsettings, makes every intervention muchmoreaccurateand informative, allowing us to better understand trending behaviours and to identify defects quickly and accurately. www.martec.co.za

Left: A PD graph on medium voltage (MV) terminations trended over time. The escalation in Qmax (mV) as the resistance of the insulation deteriorates is evident until failure occurs, which trips the supply voltage. Right: Typical partial discharge (PD) failures owing to inadequate clearance between the unscreened areas of the cable termination. PD causes the build-up of a white acid-type powder due to the ionisation of the air around the activity.

September-October 2021 • MechChem Africa ¦ 9